Many audio/video devices such as VCRs (video cassette recorders), DVD-recorders (digital versatile disk), HDD-recorders (hard disk drive), or combinations of these audio/video devices, offer the possibility to schedule recordings, i.e. to specify at which time a recording shall start. Specifically in audio/video devices which record compressed digital a/v data, e.g. DVD-recorders, it is common to provide a choice of different bit rates for recording. The user then has the possibility to record a/v data with a selected recording quality from high quality (high bit rate) to low quality (low bit rate) on the recording medium. The total length of recording varies accordingly from small to large. On a single recording medium a/v data with different recording quality can be mixed. The recording quality can usually be specified at the time of pre-programming the recording, either individually for each recording or generally for all recordings. In case the remaining storage space is not sufficient for recording a pre-programmed recording with the specified recording quality, in some audio/video devices the recording quality is automatically adapted to the available storage space. This adapted recording quality is used for all remaining pre-programmed recordings, which are to be recorded on the same recording medium. This leads to the problem that none of the recordings is recorded with high quality, which might be annoying to the user.
To overcome the above problem JP09-138698 discloses a method for recording sound data, whereby, in case the remaining storage space on a recording medium is not sufficient for a recording with high recording quality, previous recordings are re-recorded on the recording medium with lower recording quality in order to increase the available storage space. The recording quality used for re-recording the previous recordings is determined by a plurality of priority parameters. Though this approach allows to perform the pre-programmed recordings with the desired quality, especially in the case of video data a large amount of time is necessary for re-recording the previous recordings. This can be unpleasant for the user as well.
EP 0929072 discloses a digital recording system using a variable recording rate. If one or more recordings are scheduled, the system checks if these recordings can be performed with the desired bit rate. If the available free space is insufficient, the system reduces the bit rate for at least some of the scheduled recordings based on the order of scheduling.